Products such as a mobile telephone, digital AV equipment, and an IC card have been improved to have more sophisticated functions. This gives rise to an increase in the demand that semiconductor silicon chips (hereinafter, referred to as chips) provided in the products are downsized and thinned so that chips can be provided with higher density in a package. In order to provide the chips with higher density in the package, it is necessary to thin the chips to a thickness in a range of 25 μm to 150 μm.
By a grinding process, semiconductor wafers (hereinafter, referred to as wafers) which serve as bases for the respective chips are thinned. However, this weakens the strength, and cracks or warpages are likely to be formed in the wafer. In addition, the wafers weakened in strength through the thinning have difficulty being carried automatically and need to be carried manually. As can be understood from this, handling of the wafers is troublesome.
For this reason, a wafer support system is developed which holds strengths of the wafers and prevents the wafers from being cracked or warped by bonding a plate called a support plate, which is made from glass or hard plastic, to the wafers to be thinned. Because the strength of the wafers can be secured by the wafer support system, it is possible to automatically carry the semiconductor wafers after the thinning process.
The wafers and the support plates are bonded to each other by use of an adhesive tape, a thermoplastic resin, an adhesive, or the like. The wafers to which the support plate is attached are thinned. After that, the support plate is peeled off from a substrate before the wafers are diced.
Here, PTL 1 and PTL 2 disclose technology in which when bonding a support plate to a wafer, first, the wafer and the support plate are overlapped in a state in which the alignment of the wafer and the support plate is performed using an overlapping device, and the overlapped wafer and support plate are carried to an attaching apparatus and bonded.